OUAGADOUGOU - West African bloc ECOWAS has opened talks with Mali's rebel groups, including fighters linked to al Qaeda, as part of its effort to restore constitutional rule in the country in the wake of its March 22 coup, Burkina Faso's foreign minister said.

The talks are the first publicly acknowledged negotiations with the armed groups by the regional bloc since a mix of separatist rebels and Islamist gunmen took control of northern Mali following the coup in the capital.

"We have to ensure that all factions feel involved in the peace process ... it is better for them all to be present at negotiating table," minister Djibril Bassole told journalists late on Thursday.

Burkina Faso is one of ECOWAS's lead mediators in the Mali crisis. Bassole gave no details on any progress made.

ECOWAS is trying to map out a political transition and has said that it has a 3,000-strong force ready to be deployed to Mali, though analysts have questioned the bloc's readiness and appetite for desert warfare against heavily armed rebels.

The two main groups occupying Mali's north are the Tuareg-led MNLA, which wants an independent state in the desert north, and Ansar Dine, an al Qaeda-linked group which is seeking to impose Islamic law, sharia, across Mali.

But other groups including AQIM, al Qaeda's North African wing, MUJWA, which is an AQIM splinter group, and foreign fighters are also operating in the area, fuelling regional fears it has become a haven for extremists and international criminal gangs.

ECOWAS has offered to help Mali retake control of its north but plans remain vague and, before any force comes to the country, the bloc will have to resolve the political crisis.

The current interim president's term runs out this weekend and the military has proposed a national convention to choose a successor, but regional leaders and many of the country's politicians have rejected the plan.

"It is about proposing a plan that brings together the transitional government, the armed groups and other actors to find a way out of this crisis," Bassole said.

"We want the armed groups to take part in the management of the transition of the country, under conditions that we will set out," he added.

ECOWAS and the soldiers who led the coup remain at loggerheads, with West African leaders demanding they return to barracks but the former junta seeking to retain a say in the country's future.